Locking means for well tools



Aug. 25, 1959 H. s. SCHRAMM LOCKING MEANS FOR WELL TOOLS 3 Sheets-Sheet 1 Filed April 20. 1953 \.i 4 Phil Fig.2 Harry B. .S'chramm INVENTOR.

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ATTORNEY Aug. 25, 1959 H. B SCHRAMM 2,901,045 LOCKING MEANS FOR WELL TOOLS Filed April 20. 1955 3 Sheets-Sheet 2 Fig. 9

Harry B. Schramm INVENTOR.

ATTORNEY 1959 H. B. SCHRAMM LOCKING MEANS FOR WELL TOOLS 3 Sheets-Sheet 3 Filed April 20. 1953 INVENTOR. BYwwwy Fig.

ATTORNEY United States Patent 2,901,045 LOCKING MEANS non WELL roors Harry B. Schramm, Dallas, Tex., assignor to Otis Engine'ering Corporation, Dallas,- Tex., a corporation of Texas Application April 20, 1953, Serial No. 351,075 22 Claims. (Cl. 166-425) This invention relates to locking means for well tools and more particularly to a locking or anchoring means for holding a well tool in a predetermined position in the tubing string of a Well.

An object of the invention is to provide a new and improved locking means for releasably holding well tools in a predetermined position in the tubing string of a well.

Another object of the invention is to provide a new and improved locking means for well tools which is lowerable into the well by a flexible line, and which can be actuated into locked and unlocked position by jars imparted through the flexible line.

Still another object of the invention is to provide a locking means forwell tools which is of simple design and allows the well tools to have a large flow passage therethrough. I

An important object of the invention is to provide a locking means for well tools which is of extremely simple structure and economical to manufacture, and which may be landed and anchored in a landing nipple of simple and economical structure.

A further object of the invention is to provide a locking means, of the type described, having a lateral flow passage.

A still further object of the invention is to provide a selective locking means for selectively positioning and releasably holding well tools in a predetermined position in the tubing string of a well.

Additional objects and advantages of the invention will readily be apparent from the reading of the following description of devices constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

Figure 1 is a View, partly in elevation and partly in section, showing a well tool having the locking means of the invention being lowered in a well string to lock said well tool or choke in a predetermined position in the Well string fixed by a landing nipple connected in said well string;

Figure l-A is a reduced fragmentary view showing a plurality of landing nipples connected in a. tubing string;

Figure 2 is a view, similar to Figure 1, showing the manner in which the locking means locks the well tool in position in a landing nipple;

Figure 3 is a fragmentary view, partly in elevation and partly in section, showing the locking means engaged in a coupling recess provided at the lower end of a modified form of the landing nipple shown in Figures 1 and 2;

Figure 4 is a fragmentary view, similar to Figure 3, showing the locking means as used with another modified form of landing nipple;

Figure 5 is a fragmentary view, partly in elevation and partly in section showing a modified form of locking means and landing nipple and illustrating the manner in which the dimensions of the locking means and of the landing nipple may be varied to provide selectivity;

Figures 6 and 7 are fragmentary views, partly in elevation and partly in section, showing modified forms of "ice the locking means which employ selector keys; and wherein the selector keys are of different dimensions and configurations to provide selectivity of positioning of the well tool having the locking means;

Figures 8 and 9 are vertical, partly sectional views of other modified forms of the locking means which employs selector keys;

Figure 8a is an enlarged fragmentary sectional View of a portion of the locking means of Figure 8;

Figure 10 is a view, partly in elevation and partly in section, of still another modification of the locking means and landing nipple showing the well tool and locking means in anchored position; and

Figure 11 is a similar view of the device shown in Figure 10, showing the locking means in releasing position.

Referring now particularly to Figures 1 and 2, the reference numeral 10 designates generally a well tool in cluding a packer mandrel 11 on whose upper end is threaded a tubular member or body 12. The tubular body has an external annular flange 13 which provides an annular downwardly facing stop shoulder 14 which engages the upwardly and outwardly tapered stop shoulder 15 on the upper end of the landing nipple 16. The tubular body is also provided with a fishing neck flange 17 at its upper end which provides a downwardly facing undercut annular shoulder 18 engageable by any suitable running tool for removal of the well tool as will be hereinafter described.

An upper packer assembly 19 of the pressure expansible chevron type is disposed on the packer mandrel 11 and confined between the lower end 21 of the tubular member 12 and an upwardly facing annular shoulder 20 provided by a central enlargement of the packer mandrel. A lower packer assembly 22 is disposed on the packer mandrel between the downwardly facing annular shoulder 23 formed by the central enlargement of the packer mandrel and the upper end 24 of a tubular collet locking member 25 threaded on the lower end ofthe packer mandrel. The two packer assemblies are adapted to seal between the packer mandrel and the landing nipple 16 above and below the lateral ports 26 of the landing nipple.

The collet locking member has its lower end portion provided with longitudinal slots 27 which form a plurality of resilient prongs 28 adapted 'to hex inwardly and outwardly laterally. The lower ends of the prongs have outwardly extending bosses 29 which are adapted to be expanded into an annular locking groove 30 formed in the lower portion of the bore of the landing nipple below an internal annular flange 31 located immediately above the locking groove.

The bosses 29 have upwardly and outwardly extending beveled surfaces or cam shoulders 32 on their lower outer ends which are adapted to engage the downwardly and inwardly extending annular shoulder 33 of the flange 31, so that the engagement of these shoulders 32 and 33 cams the prongs 28 inwardly as the bosses move downwardly past the internal flange 31 and into the locking recess 30 of the landing nipple.

The upper shoulders 34 of the bosses are inclined downwardly and outwardly so that their engagement with the downwardly and outwardly extending lock shoulder 35 at the upper end of the locking recess 30 of the landing nipple will cam the prongs 28 inwardly when the collet locking member is moved upwardly from its locked position (Figure '2) in a manner to be hereinafter described.

A tubular expander sleeve 36 extends slidably through the tubular body 12, the packer mandrel 11 and the collet locking member 25. A connecting collar 37 is threaded on the upper end of the expander sleeve and is provided with a pair of peripheral recesses 38 which are adapted to receive shear pins (not shown) by means of which the expander sleeve is secured to a suitable running tool when the tool is to be lowered into the Well.

The lower end of the expander sleeve is provided with an external flange or head 39 having an outwardly and downwardly inclined cam shoulder 40 at its upper end which contacts the downwardly and outwardly eXtending shoulders 41 at the lower inner ends of the prongs 28 to cam the prongs outwardly into the locking position shown in Figure 2. The cam shoulder 40 of the expander is adapted to abut internal shoulders 42 at the upper end of an internal locking recess 43 formed in the inner surfaces of the bosses of the prongs 28 when the expander sleeve has been moved to the position shown in Figure 2 wherein the expander head 39 is disposed in the locking recess 43. Such engagement of the expander shoulder with shoulders 42 of the recesses in the prongs positively limits upward movement of the tubular expander sleeve relative to the collet locking member and the packer mandrel. The expander head is also provided with a downwardly and inwardly inclined cam surface 44 at its lower end which abuts the shoulders 45 at the lower end of the recesses in the prongs, and such engagement positively holds the expander sleeve in the raised locking position shown in Figure 2.

In use, if it is desired to shut oif the lateral ports 26 of the landing nipple 16, the well tool is lowered into the well by means of any suitable running tool which is secured to the connecting collar 37 of the expander sleeve by shear pins which extend into the peripheral recesses 38 of the collar. The expander head 39 is disposed below the prongs 28 of the collet locking member so that the collet member, and therefore the packer mandrel 11 and the tubular body 12, are supported in raised position on the expander sleeve by the engagement of the beveled surfaces 40 and 41 of the expander head 39 and the prongs 28, respectively. When the tool has been lowered into proper position in the landing nipple with the two packer assemblies 19 and 22 disposed on opposite sides of the lateral ports 26, the engagement of the shoulder 14 of the tubular body with shoulder of the landing nipple arrests. further downward movement of the packer mandrel. The bosses 29 of the prongs 28 are now aligned with the annular locking groove 30 of the landing nipple and are below the lock shoulder 35. An upward jar is then imparted to the expander sleeve by an upward jerk on the flexible line. The upward jar is of sutficient force to cause the expander head 39 to move upwardly into the recesses 43 in the interior of the bosses of the prongs, the camming action of the shoulders 40 and 41 expanding the collet prongs 28 during this upward movement and moving the bosses 29 into the annular locking groove 30 and into position to engage the lock shoulder. The force of this upward jar, however, is not suflicient to shear the pins connecting the collar 37 to the running tool. The engagement of the shoulder 40 of the expander head with the shoulder 42 in the locking recess in the inner surface of the bosses of the prongs 28 prevents further upward movement of the expander sleeve relative to the collet locking member. Since upward movement of the collet locking member is now prevented by the engagement of the shoulder 34 of the bosses 29 with the lock shoulder of the annular locking groove 30 of the landing nipple, further upward jars imparted to the running tool through the flexible line will now shear the pins securing the running tool to the expander sleeve. The running tool may then be raised from the well leaving the well tool locked in place.

It will be noted that downward movement of the packer mandrel is prevented by the stop shoulder 14 engaging the stop shoulder 15 at the upper end of the landing nipple, and the shoulders 34 of the collet bosses 29 engage the lock shoulder 35 to prevent upward movement of the packer mandrel out of the landing nipple. The packer mandrel is thus held securely in the landing nipple, pre- 4 eluding undue wear of the packer assemblies 19 and 22 which would take the place if the packer mandrel were free to move short distances in the landing nipple.

When it becomes desirable to remove the packer mandrel, a retrieving tool, such as the one disclosed in the patent to H. C. Otis, No. 1,898,261, is lowered into the well by means of a flexible line to deliver a downward blow to the upper end of the expander sleeve, so that theexpander head is moved downwardly out of the locking recesses 43 of the collet prongs 28, the camming action of the shoulders 44 and 45 of the expander head and the collet prongs 28, respectively, flexing the prongs outwardly to permit downward movement of the expander head. The running tool now engages the undercut shoulder 13 at the upper end of the tubular body, and upward jars delivered to the tubular body will raise the tool from the landing nipple, the camming action of the shoulders 34 of the collet bosses 29 resiliently engaging the lock shoulder 35 of the landing nipple forcing the collet prongs inwardly so that the collet bosses 29 may move upwardly past the internal flange 31 of the landing nipple.

It will thus be seen that a new and improved locking means has been provided for well tools, such as the packer mandrel 11, which includes an expander sleeve 36 pro vided with an expander head 39 for expanding the collet prongs 28 of a collet locking member 25 into locking engagement in a locking groove 30 of a landing nipple 16. It will also be apparent that the simple construction of the locking means permits use of an expander sleeve having a longitudinal bore of relatively great diameter thus providing a relatively large flow passage through the well tool, and that the packer mandrel 11 is held substantially immovable in the landing nipple so that undue wear of the packer assemblies 19 and 22 is prevented.

In Figure 3 is illustrated a modified form of a landing nipple 46 which has no locking groove, such as the locking groove 30 of the landing nipple shown in Figures 1 and 2. In this form, a locking recess 47 is provided by the lower end 48 of the landing nipple 46, the upper end 49 of the tubing section 50 and the collar or coupling 51 which connects the tubing section to the nipple. The Well tool 10 may be used with this landing nipple 46, as well as with the landing nipple shown in Figures 1 and 2, the stop shoulder 14 on said well tool engaging an upwardly facing stop shoulder at the upper end of the nipple corresponding to the stop shoulder 15 of the nipple shown in Figures 1 and 2 to position the well too] at the nipple, and the bosses 29 on the lower ends of the collet prongs 28 being disposed below and adjacent the shoulder 48 in the manner shown in Figure 3 to lock the well tool in place in the nipple. The use of the coupling 51 permits use of a cheaper simplified form of the landing nipple since the machining of an internal groove, such as the groove 30 in Figures 1 and 2, is eliminated.

Another modified form of landing nipple is shown in Figure 4, wherein the landing nipple 52 has no annular locking groove, such as the locking groove 30 of the landing nipple shown in Figures 1 and 2, but has the lower end of its bore enlarged, as at 53, to provide the annular stop shoulder 54 which serves the same function as the stop shoulder 35 of the landing nipple shown in Figures 1 and 2. In this form, also, the well tool 10 is positioned in the landing nipple by engagement of the stop shoulder 14 on the well tool with an upwardly facing shoulder at the upper end of the landing nipple 52 corresponding to the shoulder 15 of the nipple shown in Figure 1, said engagement limiting downward movement of the well tool in the mandrel and positioning the bosses 53 below the shoulder 54 as shown in Figure 4.

In all three forms of the invention just described, the internal diameter of the bore of the landing nipples is less than the diameter of the bore of the tubing string in which the nipple is connected, so that in all cases the downwardly facing stop shoulder on the well tool will .engage the upwardly facing stop shoulder of the landing nipple to limit downward movement of the well tool through the nipple and position the well tool at the landing nipple.

In Figure 5 is shown a modified form of locking means, illustrating the manner in which the locking grooves and the bosses of the collet locking members may be varied in longitudinal dimensions to permit selective locking of a well tool in a tubing string having several spaced landing nipples. The landing nipple 55 has a locking groove 56 of greater longitudinal dimension than the locking recesses shown in Figures 1. to 4. The bosses 57 on the prongs 58 of the collet locking member 58a are of substantially the same longitudinal dimension as the locking groove 56 so that the prongs 58 may be moved into expanded position by the expander head 59 of the expander sleeve 60 only when the bosses are aligned with the loci:- ing groove 56 or with a locking groove of equal or greater longitudinal dimension than the locking groove 56. The tool is not provided with any flange such as the flange 13 of the tool shown in Figures 1 and 2 which could impede downward movement of the tool through a tubing string.

In use, several landing nipples 55 are connected in a tubing string, the locking groove 56 of each nipple being of greater longitudinal dimension than the locking groove of the nipple above it. When it is desired to lock a well tool, such as the packer mandrel shown in Figures 1 and 2, in the tubing string at a particular depth at which a particular landing nipple 55 is located, a collet locking member 52 whose bosses 57 are of substantially the same longitudinal dimension as the locking groove 56 of the particular landing nipple is secured to the packer mandrel. The tool is then lowered into the tubing string, the prongs 58 keeping the bosses 57 hearing resiliently outwardly against the Wall of the tubing string. The upwardly and outwardly extending bevel surfaces or shoulders 61 at the lower ends of the bosses cam the bosses inwardly upon meeting any obstructions in the well string. The bosses 57 do not enter into the locking grooves of the landing nipples located above the selected landing nipple since the bosses are of greater length than those landing grooves, and so the bosses span such locking grooves and pass them to a lower landing nipple. When the bosses 57 are aligned with the landing groove 56 of the selected landing nipple, however, due to the action of the resilient prongs or fingers 58, the bosses are strongly biased laterally outwardly and thus they move outwardly into the locking recess. The resilient prongs or fingers press the bosses thereon into the recess with such force that the shoulders at the upper and lower ends of the bosses engage the corresponding shoulders in the landing groove to strongly resist movement of the bosses out of such groove. As a result, the downward movement of the tool will be arrested or stopped and a slackening of the flexible line on which the tool is being lowered will become apparent. The operator then knows that the well tool is positioned with the bosses 57 in the locking groove 56 and that he may draw the mandrel or central member 60 upwardly to move the expander head 59 into the internal grooves or locking recesses 62in the inner surfaces of the lower free portions of the collet prongs. The resilient force of the prongs 58 holds the 'bosses in place in the locking groove while the expander sleeve 60 is raised to bring the bevelled expander head 59 into the locking recesses 62 of the collet prongs to prevent inward flexing of the collet prongs and to thus positively lock the tool in the landing nipple at the selected position in the tubing string.

It will now be apparent that by the use of landing nipples having locking grooves 56 of different longitudinal dimensions and of collet locking members having bosses 57 of different lengths, a well tool may be locked in place in a selected one of several different landing nipples in a tubing string.

A modified form of the locking means is illustrated in Figures 6 and 7 In this form, each prong 62 of the collet locking member 63 is provided with selective locking means, which not only has a boss 64, such as the bosses 29 of the collet locking member shown in Figures 1 and 2, but also has a selector key or stop portion 65. Each of the selector keys has a downwardly facing stop shoulder 66 which is adaptedto engage an upwardly facing annular stop shoulder 67 defining the lower end of an annular selector key and stop groove 68 formed in the landing nipple 69 above the locking groove 70 in which the bosses 64 engage, thus positioning the well tool in the landing nipple. The upper ends or shoulders 71 of the selector keys are inclined downwardly and outwardly to engage the similarly inclined annular shoulder 72 defining the upper limit of the selector key and stop groove 68, the camming action between the shoulders 71 and 72 moving the collet prongs 62 inwardly as the collet locking memher is moved upwardly. The bosses 64 of the collet prongs 62 are positively held in expanded locking position by the enlarged expander portion 73a of the expander sleeve 73 which has the same structure and operates in the same manner as the expander sleeve 36 of the form first described. With this form of the locking means, the downwardly facing stop shoulder 66 of the selector keys serves to stop downward movement of the well tool, and there is no need for a projecting stop flange such as the fiange 13 of the form first described.

In use, a plurality of the landing nipples 69, Figures 6 and 7, may be connected in a tubing string at difierent depths, as generally shown in Figure 1A. Each of these landing nipples is provided with a selector key and stop groove 68 of different longitudinal dimensions than those of the selector key and stop grooves of the other landing nipples. For example, the selector key and stop groove 68a of the landing nipple shown in Figure 7 is longer than the selector key and stop groove 68 of the landing nipple shown in Figure 6. When it is desired to lock a well tool, such as the packer mandrel shown in Figures 1 and 2, in a tubing string at a particular depth, a collet locking member 63 Whose selector key 65 has a longitudinal dimension corresponding to the longitudinal dimension of the selector key and stop groove 68 of the landing nipple located at the particular depth is secured to the well tool. The tool is then lowered into the tubing string and passes through all the landing nipples located above the chosen landing nipple, since the tubular body has no projecting stop flange, such as the flange 13 of the tubular body shown in Figures 1 and 2, and since the dimensions and configurations of the selector keys of the selected collet locking member are such that they will not engage in the selector key grooves of the landing nipples located above the chosen landing nipple.

When the collet locking member passes into the selected landing nipple, however, the selector keys will enter into the selector key and stop groove 68 and the engagement of the shoulders '66 of the selector keys with the stop shoulder 67 of the groove will stop further downward movement of the tool. It will be understood that the bosses 64 may bear against the walls of the tubing string or well casing at all times, since the collet prongs are resilient so that the selector keys and bosses are biased outwardly at all times, and will enter the selector key and stop groove 68 and lock groove 70 of a landing nipple if they are of the proper dimensions and configurations. When the downward movement of the tool is arrested by the shoulders 66 and 67, the expander sleeve is moved upwardly, in the manner hereinbefore described,- to engage behind the bosses 64 of the collet prongs and thus positively lock the well tool against movement out of the landing nipple. The well tool is freed for removal in the manner set forth in connection with the previously described locking means, by driving the expander sleeve downwardly and then raising the packer mandrel. The engagement of the shoulders 71 and 72 of the selector keys assembly 81 disposed on the tubular extension.

7 and landing nipple and of the shoulders 74 and 75 of the bosses and locking groove will earn the collet prongs inwardly to permit such upward movement, after the expander is so moved downwardly.

In Figure 8 is illustrated another modified form of the locking means in which the collet locking member 76 is slidably mounted on a packing mandrel 77. On the lower end of the packing mandrel is threaded a tubular extension 78 whose lower portion is reduced to form the downwardly facing annular shoulder 79 which cooperates with a retaining ring 80 threaded on the lower end of the tubular extension to hold in place therebetween a lower packer The packing mandrel 77 is provided with an external annular flange 82 adjacent its upper end. An upper packer assembly 83 is held in place on the packer mandrel by the upwardly facing annular shoulder 84 formed by the external flange and by the downwardly facing lower end 85 of a tubular body 86 threaded on the upper end of the packer mandrel.

The packer mandrel is also provided with an external expander flange 87 disposed below the external flange 82 and above the tubular extension 78 at the lower end of the packer mandrel. The collet locking member 76 is slidably mounted on the packer mandrel below the expander flange 87, and while the tool is being lowered into the tubing string of a well the lower end 89 of said collet locking member will rest on the upper end 90 of the tubular extension. The collet locking member is provided with a plurality of upwardly extending prongs 91 having selective locking means including selector keys or stop members 92 and guide bosses 93, which are adapted to enter into the key and stop groove 94 and the guide groove 95, respectively, of corresponding configurations formed in the landing nipple 96. The selector keys or stop m-embers 92 have downwardly facing stop shoulders 97 which engage the upwardly facing stop shoulder 98 at the lower end of the key or stop groove 94 to limit downward movement of the well tool through a tubing string of which the landing nipple constitutes a section. The expander flange 87 has an upwardly and outwardly extending cam shoulder or surface 99 at its lower end which is adapted to engage an upwardly and outwardly extending cam shoulder or surface 100 at the upper end of the collet prongs to cam the collet prongs outwardly as the packer mandrel is moved downwardly after further downward movement of the collet member is arrested by the engagement of the stop shoulders 97 and 98. The selector keys 92 of the collet prongs are provided on their inner surfaces with lock recesses 101 which receive the expander flange 87, whereby the selective locking keys are held positively expanded into locking position in the groove 94 of the landing nipple. The upper shoulders 102 and 103 of the expander flange and of the recess in the inner surface of the selector keys are upwardly and inwardly beveled so that the collet prongs will be flexed outwardly by the camming engagement of these shoulders when the packer mandrel is moved upwardly relative to the collet locking member as the well tool is removed from the landing nipple.

In use, the packer mandrel is lowered into the tubing string by means of a suitable running tool on the end of a flexible line. The running tool (not shown) engages the shoulder 104 provided by the external flange 105 at the upper end of the tubular body 86. The tubing string may have several landing nipples 96, the selector grooves 94 of each landing nipple having a diiferent configuration from the selector grooves of the other nipples. Thus, by the use of a collet locking member 76 having selector locking keys 92 of the proper configuration, the packer mandrel may be caused to be located in any desired one of the landing nipples. When the packer mandrel enters the selected landing nipple, the stop shoulders 97 of the selector locking keys 92 of the collet locking member engage the stop shoulder 98 of the landing nipple and thus prevent further downward movement of the collet locking member. Downward jars imparted to the tubular body 86 will cause the expander flange 87 to move downwardly into the locking recesses 101 in the inner surface of the selector locking keys of the collet prongs, the collet prongs flexing outwardly during such movement. The expander flange now holds the collet prongs in expanded positions with the selector keys and guide bosses positively held expanded into the selector key groove 94 and the guide groove 95, respectively, of the landing n pple so that both upward and downward movement of the packer mandrel is prevented. The packer assemblies 81 and 83, which seal between the packer mandrel and the landing nipple, are now disposed below and above the lateral ports 106 of the landing nipple to prevent flow of fluid through said ports in either direction.

When it is desired to remove the packer mandrel, a suitable retrieving tool is lowered into the tubing string, by means of a flexible line, to engage the shoulder 104 of the external flange on the upper end of the tubular body 86. Upward jars imparted to the tubular body will move the packer mandrel upwardly relative to the collet locking member 76, the engagement of the shoulder 102 and 103 of the expander flange and collet prongs, respectively, camming the collet prongs outwardly to permit such upward movement of the packer mandrel. When the expander flange moves upwardly out of the locking recesses 101 in the inner surface of the selector locking keys of the collet prongs, the latter are free to flex inwardly as the tool is removed upwardly through the tubing string, the beveled shoulders 107 and 108 of the selector keys and of the bosses, respectively, camming the projecting selector keys and guide bosses of the collet prongs inwardly upon contacting obstructions during such upward movement.

Still another form of the locking means is illustrated in Figure 9, in which an expander sleeve 109 is threaded on the upper end of a packer mandrel 110. Upper and lower packer assemblies 111 and 112 are disposed on the packer mandrel on opposite sides of an external annular flange 113 of the packer mandrel. The upper packer assembly is positioned between the upper shoulder 114 of the flange 113 and the lower end 115 of the expander sleeve while the lower packer assembly is positioned between the lower shoulder 116 of the flange and a retaining ring 117 threaded on the lower end of the mandrel.

A tubular body 118 is threaded into the upper end of the expander sleeve 109 and is provided with an external flange 119 on its upper end which limits the upward movement of a collet locking member 120 that is slidable longitudinally on the tubular body. The collet locking member has prongs 121 each of which is provided with a selector locking key 122 and a guide boss 123 which are adapted to engage in the locking key and guide grooves 124 and 125, respectively, of a selected landing nipple 126 connected in a tubing string. The expander sleeve has a downwardly and outwardly extending cam shoulder 127 which is adapted to engage the downwardly and outwardly extending cam shoulders 128 on the inner lower end of the collet prongs to cam the prongs outwardly as the expander sleeve is moved upwardly in the collet locking member. The inner surfaces of the selector locking keys 122 of the collet prongs are provided with locking recesses 129, which receive the external locking flange 130 of the expander sleeve so that the selector locking keys are positively held in expanded positions after the expander sleeve has been moved upwardly in the collet locking member to the position shown in Figure 9.

In use, the packer mandrel 110 is lowered into a tubing string by means of a suitable running tool which is secured to the tubular member 118 by means of shear pins engaging in the peripheral groove 119a in the flange 119 of the tubular member. The collet locking member 120 is how in raised position on the tubular member with the-collet prongs bearing resiliently outwardly against the internal wall of the tubing string. When the collet locking member enters the-selected landing nipple 126, the selector locking keys 122 and the guide bosses 1231 move outwardly into the locking Jkey groove 124 and the guide groove 125, respectively, of the landing nipple, whereupon the engagement of .the stop shoulders 1320f the selector locking keys withlthe stop shoulder 133 of the panded to the position shown .inFigure 9 and the expander sleeve flange 130 is disposed in the locking recesses 129 in the inner surfaces ofthe selector locking keys of the collet prongs. The selector keys and guide bosses are now engaged in their respective grooves 124 and 125 and farther upward movement-of the :tubular member is prevented. Further upward jars will now shear the pins securing the running tool to the tubular member so that the running tool may be removed, leaving the packer mandrel in place in the landing nipple.

The packer assemblies 111 and :112 seal between the pack-er mandrel and the landing nipple above and below the lateral ports134 of the landing nipple.

When it is desired to remove the packer mandrel, a suitable tool is lowered into the tubing string on a flexible line to impart downwardbl-ows to the tubular member 118 to move said member downwardly. The expander sleeve 109 is likewise moved downwardly and the external locking flange 130 on said expander sleeve is thus moved downwardly out of the locking recesses 129 in the selector locking keys, so that the expander sleeve is positioned below the collet locking member. Thecollet prongs are now free to flex inwardly, the beveled shoulders 135 and 136 of theselector locking keys and guide bosses, respectively, camming the collet prongs inwardly upon meeting obstructions during upward movementof the packer mandrel through'thetubing string. The packer mandrel is lifted by theen-gagement of the retrieving tool with the undercut shoulder 137 onlthe under side 'ofthe external flange 138 at the upper end of the colletlocking member.

Still another modification of the'well tool 'is shown in Figures 110 and 11, wherein the landing nipple 139 is provided with wings 140 Which-are welded to a housing 141 forming a section of :a tubin'g string. The wings are provided with ports 142 which communicate with large apertures 143 inthehousing wall. The packing mandrel 144 is also provided with ports 145 so that fluids may flow from without the housing into the central 'bore 146 of the packer mandrel. Packer assemblies '147.and 148 mounted on the packer mandrelseal between the landing nipple and the packer mandrel above and below the ports 142 and 145.

A central control rod'or member :149extends upwardly through the collet locking member 150 threadedon the lower end of the packer mandrel. The-control rod also extends upwardly through the packer mandrel and the tubular body 1'51threaded on the/upper end of the-packer mandrel, and projects above said tubular body. An expander head 152 is threaded on the lower end of the central control rod or member and is employed to move the locking bosses 153a on the lower ends of the collet prongs 153 to expanded positions in the locking recess 154 in the lower end of the bore of the landing nipple 139.

Two sets of sealing rings 156 and 157 are mounted in suitable annular grooves in the central control rod to seal between the control .rod and the packer mandrel above and below the ports 145 when the control rod is moved to the locking .position shown in Figure 10, so that 1O flow of fluids from without the housing into the bore of the packer mandrel is prevented.

The central control rod .is also .provided with a plu rality of longitudinal grooves 187 which extend upwardly from points above and adjacent the upper set of sealing rings 156 through the external flange 158 at the upper end of the central control rod or member. When the control rod is'in lowered position, fluid may flow from without the housing 141 through the lateral ports 143, 142 and .145, into the central bore of the packer mandrel and then upwardly through the grooves 187 to the interior of the tubing string above the tubular body 151.

The device illustrated in Figures 10 and 11 may be employed to admit chemical fluids previously injectedat the surface into the annular space in the well bore exteriorly of the housing 141 and the well string in which it is connected into well fluids flowing upwardly through the housing. The chemical fluids will flow in the manner just described, through the lateral ports 143, 142 and into the bore of the packer mandrel and then upwardly through the .grooves 187 to the interior of the tubing string above the tubular body 151, where such chemical fluids, such as emulsifiers, corrosion inhibitors, paraffin inhibiters or the like, may function in treating the fluids present in the well and in treating the walls of the well flow conductor or tubing string in the usual manner. The, packer mandreland the central longitudinal control rod or member 149 may be employed to stop the flow of fluid into the housing through the lateral ports, when desired, by raising the control rod to locked position. In such position, the sealing rings 156 and 157 prevent the flow of chemical fluid through the ports 145 into the bore of the packer mandrel.

It will be seen now that a locking means has been provided which is of great-utility, being easily adapted for use with 'a great number of well tools employed for various purposes. It willalsobe seen that the locking means includes a collet-locking member having prongs which are movable outwardly by an expander head or flange on a central control member, when the latter is moved longitudinally with respect to the collet locking member, to engage locking members on said-prongs with an internal projection of a tubing string of a well, such as the downwardly facing shoulder provided by an annular recess of a landing nipple, or the coupling recess at the 'lower end of a landing nipple; that such engagement prevents displacement of the tool in the tubing string after downward movement of the tool has been stopped by the engagement of a stop shoulder of the tool with an internal projecti'on of the tubing string, such as that provided by a projecting flange or by the upper end of a section of the tubing string, or by an annular shoulder of an internal annular groove of a section of the tubing string. It will also be apparent that the central control member may be either tubular or rod shaped; that the expander head, flange or sleeve may be mounted on one end of the central member or intermediate its ends; and that packing may be mounted between the central member and another of the members of the tool within which it is movable. It will also be seen that selector locking keys may be disposed on the collet prongs so that the tool maybe locked in place in any one of several locations within a tubing string and that, alternatively, the locking grooves of spaced landing nipples-of a tubing string may be of different longitudinal dimensions, so that a Well tool havingcollet locking bosses of a selected length may be locked in place in a landing nipple being a locking groove of a corresponding longitudinal dimension.

The foregoing description of the invention is explanatory only, and changes in the constructions illustrated and described may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

l. A well tool for use in a well string having internal projections providing a downwardly facing stop shoulder and an upwardly facing stop shoulder, said tool including: an outer elongate tubular member; means on said tubular member for engaging said upwardly facing stop shoulder to arrest downward movement of said tubular member in said well string; a plurality of resilient expansible prongs mounted on said tubular member, said prongs having projections engageable with said downwardly facing stop shoulder when said prongs are in expanded position; an expander member movably mounted on said tubular member for moving said prongs into expanded position after downward movement of said tubular member has been arrested, said expander member providing a flow passage through said tool; and cooperative stop means comprising a plurality of oppositely facing shoulders on each of said expander member and said prongs co-engageable for firmly locking said expander member in prong expanding position.

2. A well tool for use in a well string having internal projections providing a downwardly facing stop shoulder and an upwardly facing stop shoulder, said tool including: an outer elongate tubular member; means on said tubular member for engaging said upwardly facing stop shoulder to arrest downward movement of said tubular member in said well string; a plurality of resilient expansible prongs mounted on said tubular member, said prongs having projections engageable with said downwardly facing stop shoulder when said prongs are in expanded position; a central longitudinal member extending through said tubular member and movable upwardly relative said tubular member to upper position; an expander member on said central longitudinal member for engaging and expanding said prongs when said central longitudinal member is moved to said upper position, said expander member providing a flow course through said tool; and cooperative stop means comprising a plurality of oppositely facing shoulders on each of said expander member and said prongs coengageable for firmly locking said expander member against movement downwardly out of prong expanding position.

3. A well tool for use in a well string having internal projections providing a downwardly facing stop shoulder and an upwardly facing stop shoulder, said tool including: an outer elongate tubular member; means on said tubular member for engaging said upwardly facing stop shoulder to arrest downward movement of said tubular member in said well string; a plurality of resilient dependent expansible prongs mounted on the lower end of said tubular member, said prongs having projections engageable with said downwardly facing stop shoulder when said prongs are in expanded position to arrest upward movement of the tubular member in said well string; a central longitudinal member extending through said tubular member and having an expander member disposed below said prongs, said central longitudinal member being movable upwardly from a lower position to an upper position relative to said tubular member and said prongs to move said expander member upwardly therewith to engagement with said prongs for holding said prongs in expanded position, said central member providing a flow course through said tool; and cooperative stop means comprising a pair of spaced oppositely facing shoulders on each of said expander member and said prongs co-cngageable for limiting upward movement of said expander member relative to said prongs and for restraining downward movement of said expander member out of position engaging said prongs.

4. A well tool for use in a well string having internal projections providing a downwardly facing stop shoulder and an upwardly facing stop shoulder, said tool including: an outer elongate tubular member; means on said tubular member for engaging said upwardly facing stop shoulder to arrest downward movement of said tubular member in said well string; a plurality of resilient dependent expansible prongs mounted on the lower end of said tubular member, said prongs having projections engageable with said downwardly facing stop shoulder when said prongs are in expanded position to arrest upward movement of the tubular member in said well string; a central longitudinal member extending through said tubular member and having an expander member disposed below said prongs, said central longitudinal member being movable upwardly from a lower position to an upper position relative to said tubular member and said prongs to move said expander to engage and move said prongs to expanded position, and cooperative stop means comprising a pair of oppositely facing shoulders on each of said expander member and said prongs coengageable for limiting upward movement of said expander member relative to said prongs, said stop means also releasably restraining movement of said expander member downwardly from expanding position, said central longitudinal member having a longitudinal bore for allowing flow of fluid through said central longitudinal member.

5. A well tool for use in a well string having a plurality of spaced pairs of locking recesses of different longitudinal lengths and configurations, each pair of locking recesses providing an upwardly facing stop shoulder and a downwardly facing stop shoulder, said tool including: an outer elongate tubular member; a plurality of resilient expansible means mounted on said tubular member, each of said expansible means having projections forming a selector boss and a guide boss of longitudinal dimensions and configurations corresponding to and engageable in a selected pair of said pairs of locking recesses during downward movement of said tool through said well string, said selector boss having a downwardly facing stop shoulder engageable With the upwardly facing stop shoulder of the selected pair of locking recesses to arrest downward movement of said tool in said well; and an expander member movably mounted on said tubular member for engaging and expanding said expansible means to lock said bosses in said selected pair of recesses after downward movement of said tool has been arrested, one of said bosses providing an upwardly facing stop shoulder for engaging said downwardly facing stop shoulder of said recesses to prevent upward movement of said tool in said well string when said bosses are in expanded position.

6. A well tool for use in a well string having a plurality of spaced pairs of locking recesses of different longitudinal lengths and configurations, each pair of locking recesses providing an upwardly facing stop shoulder and a downwardly facing stop shoulder, said tool including: an outer elongate tubular member; a plurality of resilient expansible means mounted on said tubular member, each of said expansible means having projections forming a selector boss and a guide boss of longitudinal dimensions and configurations corresponding to and engageable in a selected pair of said pairs of locking recesses during downward movement of said tool through said well string, said selector boss having a downwardly facing stop shoulder engageable with the upwardly facing stop shoulder of the selected pair of locking recesses to arrest downward movement of said tool in said well; an expander means movably mounted on said tubular member for engaging and expanding said expansible means, after downward movement of said tool has been arrested, to lock said bosses in said selected pair of recesses; one of said bosses providing an upwardly facing stop shoulder for engaging said downwardly facing stop shoulder of said recesses to prevent upward movement of said tool in said well string when said bosses are in expanded position; and cooperative stop means on said expander member and said expansible means for limiting upward movement of said expander relative to said bosses.

7. A well tool for use in a well string having a plurality of spaced pairs of locking recesses of different longitudinal lengths and configurations, each pair of locking recesses providing an upwardly "facing stop shoulder {and-a downwardly facing stop shoulder, said tooldncluding: @an outer elongate tubular member; a plurality inf-resilient expansible means mounted on saidztubular member, ,each of said expansible means having projections forming a selector boss and a guide ,bossof longitudinalrdimensions and configurations corresponding to and en a eable in a selected pair of said pairs of locking recesses during downward movement of said toolthrough said wellstring, said selector boss having aidownwardly facing stop shoulder engageable with the upwardly facing stop shoulderof the selected pair of locking recesses arrest downward movement of said tool -in said Wellaand amelongate central longitudinal member having ,anexpander member thereon and movable longitudinally ,in said tubular member for moving said expander member :to a position engaging said expansible means, vafter downward movement of said tool has been arrested, to lock said-bosses in said selected pair of recesses; one of said bosses providing an upwardly facing stop shoulder for engaging said downwardly facing stop shoulder of said recesses to prevent upward movement of said tool in said well stringlwhen said bosses are in expanded position, said central longitudinal member having valongitudinal bore for allowing flow of fluid through said central longitudinal member.

.8. A well tool for use in awell string having a plurality of spaced .pairs of locking recesses of different longitudinal lengths and configurations, each pairtof locking recesses providing an upwardly facing stop shoulder and a downwardly facing stop shoulder, said tool including: an outer elongate tubular member; a plurality of resilient expansible means mounted :on said tubular member, each of said expansible means having projections forming a selector boss and a guide boss of longitudinal dimensions and configurations corresponding to .and engageable in ,a selected pair of said pairs of locking recesses during downward movement of said tool through said well string, said selector boss having a downwardly facing stop shoulder engageable with the upwardly facing stop shoulder of the selected pair of locking recesses to arrest downward movement of said tool in said well; an elongate central longitudinal member having an expander means thereon movable longitudinally in said tubular member for moving said expander means to a position engaging said expansible means, after downward movement of said tool has been arrested, to lock said bosses in saidselected pair of recesses; one of said bosses providing an upwardly facing stop shoulder for engaging said downwardly facing stop shoulder of said recesses to prevent upward movement of said tool in said Well string when said bosses are in expanded position; and cooperative stop means on said expander member and said expansible means for limiting upward movement of said expander relative to said bosses; said central longitudinal member having a longitudinal bore for allowing flow of fluid through said central longitudinal member.

9. A well tool for use in a well string having a plurality of spaced pairs of locking recesses of different longitudinal lengths and configurations, each pair of locking recesses providing an upwardly facing stop shoulder and a downwardly facing stop shoulder, said tool including: an outer elongate tubular member; a plurality of resilient expansible means mounted on said tubular member, each of said expansible means having projections forming a selector boss and a guide boss of longitudinal dimensions and configurations corresponding to and engageable in a selected pair of said pairs of locking recesses during downward movement of saidtool through said well string, said selector boss having a downwardly facing stop shoulder engageable with the upwardly facing stop shoulder of the selected pair of locking recesses to arrest downward movement of said tool in said well; an elongate central longitudinal member having an expander member thereon movable longitudinally in said tubular member for moving said expander means to a positionengaging saidexpansible means-to lock said bosses insaidlselected pair of recesses; one of:said bosses providing an upwardly facing stop shoulder for engaging said downwardly facing stop shoulder of said recesses to prevent upward movementofsaid tool insaid well stringwhen said bosses:are in expanded position, said central longitudinal member having a longitudinal bore for allowing .flow ;of fluid through said =-central longitudinal member; and sealing means-on said tubular member engageable with the well string for sealing'between said tubular member and said well string.

'10. A -well stool including: an elongate body member havingan axial passage; said body member having an outwardly extending external flange adjacent the upper end thereof providing a downwardly :facing stop shoulder which is adapted to engage an upwardly facing stop shoulder of a well string through whichsaid body member may be lowered to limit the downward movement of said body member, said body member having a-resilient expansible means on its lower end, provided with external locking bosses, said expansible means 'having .an axial passage concentric with the axial bore of said body memher; an elongate control member extending through said axial passage and having an expander on its lower end disposed below said expansible means, said expander e'ngaging and expanding :the locking bosses on said expansible means upon upward movement of said elongate control member relative to said body member, said control member having ,aaflow course therethrough providing a flow course through said tool; and oppositely facing shoulder-s on each of said expansible means and said control member, said shoulders being coengageable :to releasably retain said expander member in position engaging the locking bosses on said expansible means for holding said locking bosses in saidexpanded locking position.

11. A well tool including: an elongate tubular member having an axial passage, said tubular member having an outwardly extending external flange adjacent the upper end thereof providing a downwardly facing-stop shoulder which is adapted to :engage an upwardly facing stop shoulder of a well string through which said tubular member may be lowered to limit the downward movement of said tubular member, said tubular member having a resilient expansible means on its-lower end, said expansible means having an axial passage concentric with the axial bore of said tubular member; and an elongate control member extending through said axial passage and having an expander on its lower end disposed below said expansible means, said expander having a downwardly and outwardly extending shoulder adapted to enter into the lower end of the axial passage of said expansible means to expand said expansible means outwardly upon upward movement of said elongate control member relative to said tubular member, said expander having a downwardly and inwardly extending lower shoulder below said downwardly and outwardly extending shoulder, said expansible means having groove means on the lower end of the axial passage therein adapted to receive said expander, said lower shoulder of said expander being engageable within said groove means in said expansible means to releasably lock said expander member against downward movement from expanding position by preventing downward movement of said elongate control member relative to said tubular member, said control member having a flow course therethrough providing a flow course through said tool.

12. A well tool for use in a well string having a plurality of pairs of stop shoulders, each pair of stop shoulders being spaced longitudinally in said well string from the other pairs and each including a downwardly facing stop shoulder and an upwardly facing stop shoulder, the shoulders of each pair being spaced apart a longitudinal distance different from the spacing of the shoulders of the other pairs, the distance between shoulders being .progressively greater on each successive lower pair of shoulders, each of said pairs of stop shoulders being designed to be engaged in stopping and locking position by stop and locking means of a separate particular well tool formed with external stop and locking shoulders thereon of a configuration conforming to the configuration of a partlcular pair of well string stop shoulders to position said well tool at such particular selected pair of shoulders, said tool including: a tubular body having a resilient locking portion comprising a plurality of radially spaced longitudinally extending prongs connected to a common member at one end and free for resilient lateral movement at the other end between expanded and retracted positions, each of said prongs having on its free movable end outwardly extending boss means having an external longitudinal configuration providing a downwardly facing stop shoulder and an upwardly facing stop shoulder thereon spaced apart longitudinally a distance corresponding to the longitudinal distance between the shoulders of said particular selected pair of well string stop shoulders, so as to be engageable in stopping and locking engagement with only such pair of stop shoulders to position said well tool in said well string only at such particular pair of shoulders, engagement of said downwardly facing stop shoulder of said boss means with said upwardly facing stop shoulder of said particular selected pair of stop shoulders limiting downward movement of said well tool in said well string to position said well tool therein at said particular pair of shoulders; and a central member movable longitudinally in said body and having an enlarged member thereon movable therewith into position engaging the free movable ends of said prongs to hold said free ends of said prongs in expanded position with the stop shoulders of the boss means disposed to engage said particular pair of well string stop shoulders, in which position said upwardly facing boss means stop shoulder is engageable with said downwardly facing stop shoulder of said pair of well string stop shoulders to prevent upward movement of said well tool from such position in said well string, said tubular member providing a flow course through said well tool.

13. A well tool including: an elongate tubular member having a longitudinal passage, said tubular member having an outwardly extending external flange adjacent the upper end thereof and integral therewith providing a downwardly facing stop shoulder which is adapted to engage an upwardly facing stop shoulder of a well string through which said tubular member may be lowered to limit the downward movement of said tubular member, said tubular member having a resilient expansible means at its lower end provided with external locking projections, said expansible means having a longitudinal passage communicating with the bore of said tubular member, an elongate tubular control member extending through said longitudinal passages and having an expander on its lower end disposed below said expansible means, said expander engaging and expanding the locking projections of said expansible means upon upward movement of said elongate control member relative to said tubular member; said resilient expansible means having an internal groove therein provided with oppositely facing shoulders; said control member having an external projection thereon also having oppositely facing shoulders, one of said shoulders on the projection of said control member being engageable with one of the shoulders of said internal groove in said expansible means to releasably lock said expander member in its upper expanding position against downward movement therefrom, the other of said shoulders on said projection being engageable with the other of said shoulders of said groove for limiting upward movement of said expander relative to said tubular member and said expansible means.

14. A well tool for use with a landing nipple having an upwardly facing stop shoulder and a downwardly facing stop shoulder, said tool including: an elongate tubular member having a resilient locking section providing laterally movable members; a first means on said laterally movable members of said resilient section engageable with said upwardly facing shoulder of said landing nipple for limiting downward movement of said tubular member through said landing nipple; a second means on said laterally movable members of said resilient section engageable with said downwardly facing stop shoulder of said landing nipple to prevent upward movement of said tubular member from said nipple; a third means slidable in said tubular member for movement downwardly to a lower position for engaging the laterally movable members of said resilient locking section and holding said laterally movable members and said second means thereon in position for engaging said downwardly facing stop shoulder of said landing nipple, said third means having a flow course therethrough; and oppositely facing shoulders on each of said third means and said resilient locking section, said shoulders being coengageable to releasably hold said third means in said lower position.

15. A well tool for use with a landing nipple having an upwardly facing stop shoulder and a downwardly facing stop shoulder, said tool including: an elongate tubular member having a resilient locking section providing laterally movable means; a first stop means on said laterally movable means of resilient locking section of said tubular member engageable with said upwardly facing shoulder of said landing nipple for limiting downward movement of said tubular member through said nipple; a second stop means on said laterally movable means of said resilient locking section engageable with said downwardly facing stop shoulder of said landing nipple to prevent upward movement of said tool from said nipple; a third means mounted in said tubular member for longitudinal movement therein to a position engaging said resilient locking section and holding said laterally movable means and said second stop means thereon in position for engaging said downwardly facing stop shoulder of said landing nipple, said third means being movable longitudinally of said tubular member out of holding engagement with said laterally movable means to permit said resilient locking section to flex to permit said laterally movable means and said second stop means thereon to move out of stop shoulder engaging position, and oppositely facing shoulders on each of said third means and said laterally movable means of said resilient locking section disposed to engage each other to releasably hold said third means in position engaging said resilient locking section and preventing said second stop means from moving out of a stop shoulder engaging position, said third means having a flow course therethrough to permit fluid flow through said tool.

16. A well tool for use in a well string having means providing a downwardly facing stop shoulder and an upwardly facing stop shoulder, said tool including: a tubular outer member having integral resilient outwardly expansible locking means; a central member slidably disposed in said tubular outer member; said central member having means providing a flow passage through said tubular outer member; lock means on said central member movable longitudinally therewith for engaging and holding said expansible means in expanded position wherein said expansible locking means is positioned to engage said downwardly facing shoulder to limit upward movement of said tool; said central member and said outer member having coengageable means comprising oppositely facing shoulders on said central member and oppositely facing shoulders on said outer member engageable when said central member has been moved to dispose said lock means thereon in position to engage and hold said expansible locking means in looking position, such engagement of the shoulders on said central member and on said lock means releasably holding said central member in such position in which said lock means engages said expansible locking means to hold said locking means in locking position; and means on said tool engageable with said upwardly facing shoulder for limiting downward movement of said tool in said well string.

17. A well tool adapted to be moved into and out of a selected landing nipple in a well string provided with a plurality of landing nipples each having a selective locking groove of a different longitudinal configuration from the groove of the other landing nipples, each of said grooves having a downwardly facing lock shoulder and an upwardly facing stop shoulder, said tool including: an outer tubular member, a resilient stop and locking means on said tubular member, said means including a plurality of circumferentially spaced longitudinally extending resilient fingers each having one end connected to a common support member and its other end free for resilient lateral movement, the free end of each of said fingers having an outwardly projecting selective locking boss portion providing an upwardly facing lock shoulder and a downwardly facing stop shoulder with a longitudinal configuration corresponding to the longitudinal configuration of the groove of said selected landing nipple and adapted to engage in said groove to position said well tool at said nipple; and a central member movable longitudinally in said outer member and having a lock member thereon, said central member being movable with respect to said outer member between upper and lower positions, said lock member being disposed to engage the movable free end portions of the resilient fingers of said stop and locking means when said central member is in one of said upper and lower positions to hold said selective locking boss portion thereof against movement from projecting position toward retracted nonprojecting position, whereby said selective locking boss portion is positively held in such projecting position with the shoulders thereon disposed to engage the locking groove stop shoulders of said landing nipple to lock said tool in said selected landing nipple when said selective locking boss portion is engaged in the groove of said selected landing nipple.

18. A well tool of the character set forth in claim 17 wherein means is provided on said central member and on the stop and locking means engageable to prevent movement of said selective locking portion to retracted position, said means comprising a projection on said central member and a recess on said stop and locking means providing opposed shoulders on said projection and opposed shoulders in said recess engageable with each other to releasably hold said projection in said recess.

19. A Well tool adapted to be moved into and out of a selected landing nipple in a well string provided with a plurality of landing nipples each having a selective locking groove of a different configuration from the grooves of the other landing nipples, each of said grooves having a downwardly facing lock shoulder and an upwardly facing stop shoulder, said tool including: an outer tubular member, a resilient stop and locking means on said tubular member, said means including an annular common support member and a plurality of circumferentially spaced longitudinal extending resilient fingers each having one end connected to said common support member and its other end free for resilient lateral movement, the free end of each of said fingers having an outwardly projecting selective locking boss portion providing an upwardly facing lock shoulder and a downwardly facing stop shoulder with a configuration corresponding to the configuration of the groove of said selected landing nipple and adapted to engage in said groove to position said well tool at said nipple; and a central member movable longitudinally in said outer member and having a lock member thereon, said central member being movable with respect to said outer member between upper and lower positions, said lock member being disposed to engage the movable free end portions of said resilient fingers of said stop and locking means when said central member is in one of said upper and lower positions to hold said selective locking boss portions thereof against movement from projecting position toward retracted non-projecting position, whereby said selective locking boss portions are positively held in such projecting position with the shoulders thereon disposed to engage the locking groove stop shoulders of said landing nipple to lock said tool in said selected landing nipple when said selective locking boss portions are engaged in the groove of said selected landing nipple, and oppositely facing shoulders on each of said central member and said outer tubular member engageable to releasably hold said central member in said one position in which said lock member thereon is disposed to prevent movement of said selective locking boss portions of said stop and locking means toward retracted position.

20. A well tool for use in a well string having means therein providing a downwardly facing lock shoulder and an upwardly facing stop shoulder, said tool including: a tubular outer member having integral resilient downwardly extending locking means; said downwardly extending resilient locking means comprising a plurality of circumferentially spaced longitudinally downwardly extending resilient fingers, each of said fingers having at its lower free end means providing an outwardly extending upwardly facing lock shoulder and a downwardly outwardly extending stop shoulder thereon, said means forming said shoulders being resiliently movable with said locking means between locking and retracted positions; a central member slidably disposed in said tubular outer member; means on said central member movable longitudinally therewith in said outer tubular member between positions engaging and holding said expansible locking means in locking position wherein said upwardly facing lock shoulder is disposed in position to engage said downwardly facing lock shoulder of said tubing to limit upward movement of said tool; and oppositely facing shoulder means on each of said central member and said tubular outer member co-engageable when said central member is in position engaging said expansible locking means for releasably holding said central member against downward movement of said central member out of said engaging position; said central member having means providing a flow course therethrough whereby fluids may flow through said tool.

21. A device of the character set forth in claim 12 wherein: the central member is tubular whereby an axial flow course is provided permitting flow of fluids through said central member.

22. A well tool of the character set forth in claim 19 wherein said oppositely facing shoulders on said central member are provided at the opposite ends of an annular projection on said central member, and said oppositely facing shoulders on said outer tubular member are formed at the opposite ends of the groove formed in the inner surfaces of the resiliently movable ends of said resilient collet fingers, said annular projection being disposed to be received in said grooves in said collet fingers with the oppositely facing shoulders on said projection and said groove being engageable to prevent displacement of said projection from said groove.

References Cited in the file of this patent UNITED STATES PATENTS 2,246,811 Otis June 24, 1941 2,272,388 Williams Feb. 10, 1942 2,392,244 Hooser Jan. 1, 1946 2,401,119 Taylor May 28, 1946 2,506,680 Otis May 9, 1950 2,640,546 Baker June 2, 1953 2,673,614 Miller Mar. 30, 1954 2,698,056 Marshall Dec. 28, 1954 

